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For some time now I Have been riding around with a 160 tire on the stock 3.5" rim. 
While this does work it really shouldnt be done. After countless debates and a lotta cold hard facts I must finally agree. Not only is it unsafe by deforming the tire but it restricts the full potential of the availible tread at low lean angles. And all N all really just dont look right.
So with some help from Krey (Thanks again bro)
, We located and aquired a 89 Rear Gixxer Rim from flea bay and the work began. Please pardon some of these shots my camera was acting up on me.
First things first, figguring out all the potential differences in the two rims.
#1 Is the obvious...The rim hoop itself is 1" wider
#2 The Gixxer's rim has a wider center hub (by approx 3/4 of an inch or roughly 20mm)
#3 The Gixxer has a wider axle diam. making the wheel bearings on this wheel useless. You must swap these out for the GSXF Bearings. The O.D. are the same size so short of actually pulling these out its no big deal.
(The pic below shows the Gixxer Bearing on the right.)
Along with the bearings being larger the inner wheel spacer is larger and longer as well. (GSXF Spacer is on left)
(Side view)
This is an extreemly important spacer as it prevents the wheel bearings from collapsing into the wheel hub under stress form the axle bolt and the pressure of leans and turns. Using the Gixxer Spacer wouldnt be an option IMHO as it would leave a lot of slop in the hub and cause wheel balance issues later. So I decided to go with the GSXF spacer and pack it out using hardened steel washers to make up the difference. Idealy the best thing to do here is to just have one fabbed up to the proper dimentions However this option wasnt available to me In the time I needed to finish this.
Placing 2 on each end of the spacer made up the difference quite nicely.
The sprocket carrier for both rims are identical in this case so it was a simple swap as I wanted to stay with a 47T sprocket as opposed to the 45T that came with the new wheel. However the rotors are different. The Gixxer uses a 5 bolt mount & the Katana only has 4.
Using the sissor jack from my GTP, I was able to widen the swingarm to the needed width to place the rim, spacers, and caliper bracket in place for sizing and alignment. From about 8 3/4" to about 9 1/2" *note that distance will be reduced later to about 9 1/4" but made it much easier to place the wheel in to place ATM.
Once the wheel was in place I noticed that there simply wasnt enough axle room to safely get the nut on and the cotterpin in to hold it together.
After consulting with the KR Gawds in the CB (Thank you Court & Krey) We came up with the going solution to this lil problem. By shaving off about 3-4 mm from the caliper bracket (swingarm side) It gave me enough clearance to properly secure the axle nut. However it created another problem. The caliper itself wasnt centered over the rotor any longer.
While this may not bother some to me it was off. And off is wrong.
Solution: Pull the bracket back out and remove the material (approx. 2mm)from the caliper mounting points on the opposite side closest to the wheel. this caused the mount bolts for the caliper to come dangerously close to the rotor so a few lock washers on the back side were installed to correct the issue. Its still a few MMs out but much better then it was.
And I didnt want to sacrifice any more rigidity to the bracket itself. A simple bend of the tabs on the caliper strut made it fall into perfect alignment.
With all the pieces in place and to my liking it was time to prep and paint the wheel.
Mount the new rubber on it.
I was thinking about going wider in the begining (170)but thought better of it as I would only be right back in the same boat
And deforming the tire once again, basicly making this all for looks instead of function. Im glad I didnt.
Once it was all painted, mounted and balanced. I did the final assembly.
A few test flights later and It was good ta go!!! Leans feel much smoother and far more stable as opposed to the falling off the cliff feeling I was getting on the deformed tire!
And a few more shots of the LEDs I installed while waiting for my new tire to arrive.
Im not a Bling-Bling Kinda guy (Shel talked me into it) so I went modest here. A few pods in the engine compartment and oil cooler area, stips under the swing arm and a new tail light for the 2up seat for the AUG ride.
The LEDs sway side to side (Knight Rider Style) till the brakes are applied then they all go solid.
In the end I like how the swap went but think a lot of issues can be avoided by simply fabbing up a longer axle bolt to eliminate the need to mill down the bracket. As well as packing out the inner hub spacer. Had it not been for axle length issues everything would have line up perfectly using the stock bits as is. Having access to a good machinest (Spelling?) Would make this a very simple job...at least for me!
Thanks for all the help and insight guys! If it wasnt for the KRew and Jr. keeping me company Id sill be sitting on the old 3.5"
While this does work it really shouldnt be done. After countless debates and a lotta cold hard facts I must finally agree. Not only is it unsafe by deforming the tire but it restricts the full potential of the availible tread at low lean angles. And all N all really just dont look right. So with some help from Krey (Thanks again bro), We located and aquired a 89 Rear Gixxer Rim from flea bay and the work began. Please pardon some of these shots my camera was acting up on me.First things first, figguring out all the potential differences in the two rims.
#1 Is the obvious...The rim hoop itself is 1" wider
#2 The Gixxer's rim has a wider center hub (by approx 3/4 of an inch or roughly 20mm)
#3 The Gixxer has a wider axle diam. making the wheel bearings on this wheel useless. You must swap these out for the GSXF Bearings. The O.D. are the same size so short of actually pulling these out its no big deal.
(The pic below shows the Gixxer Bearing on the right.)
Along with the bearings being larger the inner wheel spacer is larger and longer as well. (GSXF Spacer is on left)
(Side view)
This is an extreemly important spacer as it prevents the wheel bearings from collapsing into the wheel hub under stress form the axle bolt and the pressure of leans and turns. Using the Gixxer Spacer wouldnt be an option IMHO as it would leave a lot of slop in the hub and cause wheel balance issues later. So I decided to go with the GSXF spacer and pack it out using hardened steel washers to make up the difference. Idealy the best thing to do here is to just have one fabbed up to the proper dimentions However this option wasnt available to me In the time I needed to finish this.
Placing 2 on each end of the spacer made up the difference quite nicely.
The sprocket carrier for both rims are identical in this case so it was a simple swap as I wanted to stay with a 47T sprocket as opposed to the 45T that came with the new wheel. However the rotors are different. The Gixxer uses a 5 bolt mount & the Katana only has 4.
Using the sissor jack from my GTP, I was able to widen the swingarm to the needed width to place the rim, spacers, and caliper bracket in place for sizing and alignment. From about 8 3/4" to about 9 1/2" *note that distance will be reduced later to about 9 1/4" but made it much easier to place the wheel in to place ATM.
Once the wheel was in place I noticed that there simply wasnt enough axle room to safely get the nut on and the cotterpin in to hold it together.
After consulting with the KR Gawds in the CB (Thank you Court & Krey) We came up with the going solution to this lil problem. By shaving off about 3-4 mm from the caliper bracket (swingarm side) It gave me enough clearance to properly secure the axle nut.
However it created another problem. The caliper itself wasnt centered over the rotor any longer.
While this may not bother some to me it was off. And off is wrong.
Solution: Pull the bracket back out and remove the material (approx. 2mm)from the caliper mounting points on the opposite side closest to the wheel. this caused the mount bolts for the caliper to come dangerously close to the rotor so a few lock washers on the back side were installed to correct the issue. Its still a few MMs out but much better then it was.
And I didnt want to sacrifice any more rigidity to the bracket itself. A simple bend of the tabs on the caliper strut made it fall into perfect alignment.With all the pieces in place and to my liking it was time to prep and paint the wheel.
Mount the new rubber on it.
I was thinking about going wider in the begining (170)but thought better of it as I would only be right back in the same boat
And deforming the tire once again, basicly making this all for looks instead of function. Im glad I didnt.Once it was all painted, mounted and balanced. I did the final assembly.
A few test flights later and It was good ta go!!! Leans feel much smoother and far more stable as opposed to the falling off the cliff feeling I was getting on the deformed tire!
And a few more shots of the LEDs I installed while waiting for my new tire to arrive.
Im not a Bling-Bling Kinda guy (Shel talked me into it) so I went modest here. A few pods in the engine compartment and oil cooler area, stips under the swing arm and a new tail light for the 2up seat for the AUG ride.
The LEDs sway side to side (Knight Rider Style) till the brakes are applied then they all go solid.
In the end I like how the swap went but think a lot of issues can be avoided by simply fabbing up a longer axle bolt to eliminate the need to mill down the bracket. As well as packing out the inner hub spacer. Had it not been for axle length issues everything would have line up perfectly using the stock bits as is. Having access to a good machinest (Spelling?) Would make this a very simple job...at least for me!
Thanks for all the help and insight guys! If it wasnt for the KRew and Jr. keeping me company Id sill be sitting on the old 3.5"
This was supposed to wait till winter but my rear tire was shot and there was no way I was gonna go on a 2 up ride with Shel knowing it was in that condition.
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